package com.gome.gop.common;

import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;

/**
 * @Title:
 * @Description: 上下文获取
 * @Author:chengcheng7
 * @Since: 2020/7/14 15:50
 * @Copyright:Copyright (c) 2018 - 2100
 * @Company:gome
 * @Version:1.1.0
 */
@Component
public class SpringContextHolder implements ApplicationContextAware {
    private static ApplicationContext applicationContext;
    
    /**
     * 实现ApplicationContextAware接口的context注入函数, 将其存入静态变量.
     */
    @Override
    public void setApplicationContext(ApplicationContext applicationContext) {
        SpringContextHolder.applicationContext = applicationContext;
    }
    
    /**
     * 取得存储在静态变量中的ApplicationContext.
     */
    public static ApplicationContext getApplicationContext() {
        checkApplicationContext();
        return applicationContext;
    }
    
    /**
     * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型.
     */
    @SuppressWarnings("unchecked")
    public static <T> T getBean(String name,Class<T> clazz) {
        checkApplicationContext();
        return (T)applicationContext.getBean(name);
    }
    
    /**
     * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型.
     */
    @SuppressWarnings("unchecked")
    public static <T> T getBean(Class<T> clazz) {
        checkApplicationContext();
        return (T)applicationContext.getBeansOfType(clazz);
    }
    
    /**
     * 清除applicationContext静态变量.
     */
    public static void cleanApplicationContext() {
        applicationContext = null;
    }
    
    private static void checkApplicationContext() {
        if (applicationContext == null) {
            throw new IllegalStateException("applicaitonContext未注入,请在applicationContext.xml中定义SpringContextHolder");
        }
    }
    
}